1. Field of the Invention
This invention relates to and has among its objects the provision of novel water-insoluble but active enzyme products and methods for preparing them. Further objects of the invention will be evident from the following description wherein parts and percentages are by weight unless otherwise specified.
2. Description of the Prior Art
In recent years there has been considerable interest in preparing enzymes in insolubilized (sometimes referred to as immobilized) form. Such products enable enzyme-catalyzed reactions to be carried out in a simplified and efficient manner. Typically, the insolubilized enzyme is placed in a cylindrical vessel and a solution of the substrate to be reacted is passed through the enzyme column. The reaction takes place within the column and the effluent liquor contains the reaction products. With this system the enzyme can be used repeatedly for processing fresh batches of the substrate. Various techniques have been advocated for preparing insolubilized enzymes. One procedure is to entrap the enzyme in polymerizing polyacrylamide; another is to adsorb it on insoluble media such as ion exchange resins, alumina, etc.
Difficulty, however, has been encountered in preparing immobilized sulfhydryl-containing enzymes such as urease. Chemical cross-linking agents have a deleterious effect on the enzyme. For example, attempts at insolubilizing urease with such conventional agents as glutaraldehyde, cyanogen bromide, and substituted agarose gels were unsuccessful in that they substantially reduced the urease activity.